Impact of cancer on cryopreserved sperm quality and fertility: A cohort study

Abstract Background Sperm quality at cancer diagnosis is often compromised by the disease and any given gonadotoxic treatment will further diminish fertility. Objectives Here, we aim to analyze the cryopreserved sperm quality according to the cancer types as well as the fertility outcomes. Methods Our study included all cancer patients who cryopreserved sperm over 20 years at Erasme Hospital Brussels (from 1999 to 2019). First sperm samples from 111 hematologic, 104 testicular, 19 prostate, 28 gastrointestinal, and 16 neurological cancer patients were compared. Results Oligozoo‐asthenozoospermia was observed in 30% of the samples, including 19.33% with severe oligozoospermia (<5 million/ml). Our results showed a significant reduction in sperm concentration among testicular cancer (p < 0.01). No significant differences in progressive motility, sperm volume, and number of frozen straws were observed. Significant correlations were found between sperm concentration and cancer type (p <0.01) as well as patients' age (p <0.01). Twenty‐eight cancer survivors returned for using their cryopreserved sperm (9.33%), fertilization rate was 60.5% and implantation rate was 29.6%. There was no correlation between sperm concentration and fertility outcomes. Conclusion Our results confirm the negative impact of cancer on sperm quality without affecting assisted reproductive technology (ART) success rate, which is utterly important as a male reproductive health perspective. All cancer patients should be counselled and offered fertility preservation options as a gold standard.


| INTRODUCTION
Cancer has affected 18.1 million people worldwide in 2018, leading to around 9.6 million deaths. 1 In Belgium, cancer incidence is increasing with more than 70,000 new cases in 2018, among which 42,593 were male patients. 2,3 The most common cancers in men in reproductive age are testicular neoplasia, hematologic malignancies (including leukemia, Hodgkin and non-Hodgkin lymphoma), colorectal cancers, and brain tumors. 2,4,5 Treatments such as chemotherapy and radiotherapy have well-known gonadotoxic effects depending on the type of drugs as well as the doses and localization of the radiation. 2,6 The cancer itself and the treatment may both impair male fertility by affecting sperm DNA and spermatogenesis, leading to temporary or permanent azoospermia. [7][8][9] Moreover, evolution of the disease and response to treatment may be unpredictable and it is not excluded that a patient will eventually benefit from a second-line gonadotoxic treatment not initially planned. 10 Since 2018, the cryopreservation of semen is covered by the insurances up to 45 years of age in Belgium for oncological indications including solid tumors, hematopoietic or lymph node malignancies, testicular neoplasia (with or without adjuvant treatments), and all indications of hematopoietic stem cell transplantation.
The sperm straws are stored for a renewable period of 10 years, unless otherwise requested by the patient himself.
Nowadays, the number of cancer survivors is increasing through the development of sensitive screening tools to detect early stage cancers and of new targeted cancer therapies. 6,11 Hence, in a society where both women and men become parents later in life, 12 an increasing number of cancer patients do not have children or do not yet complete their family projects at the time of diagnosis. Therefore, the possibility of sperm banking before starting their potentially gonadotoxic therapies is crucial for their future quality of life as it offers them the opportunity to have children after remission. 2,[4][5][6] This procedure is highly recommended by guidelines and considered as a gold standard to preserve fertility in adults and adolescents. 13,14 Previous studies showed sperm quality impairment before the gonadotoxic treatment due to cancer itself, 10 focusing mainly on the testicular cancers and hematologic malignancies. 9,11 Few authors evaluated the fertility outcomes, [15][16][17] emphasizing the importance of the use of frozen sperm for male cancer patients.
In this study, we aim to address these questions in a large cohort who cryopreserved sperm over a two-decade period. The characteristics of the sperm were compared according to the type of cancer with the objective to further evaluate the correlation between the type of cancer and sperm quality. Other potential confounding factors such as smoking, alcohol consumption, andrology history, and the age of the patient at diagnosis were also considered. Fertility outcomes were analyzed as a secondary objective.

| Study design
This monocentric retrospective study was conducted in Brussels, at the CUB-Erasme Hospital, Université Libre de Bruxelles. All data were collected from electronic medical records. The study was approved by the Erasme Ethical Committee (P2019/397).
The patients included in the study were male cancer patients, who performed sperm cryopreservation procedures for fertility preservation at the time of diagnosis.
Information regarding the type of cancer, sperm analysis parameters, smoking or alcohol consumption, andrology history, age, treatment already received, and history of assisted reproductive technology (ART) were collected from the medical reports.
Oncological diseases were classified into different categories: hematologic malignancies (including leukemia and lymphoma), testicular, prostate, colorectal, brain, and other less common cancer types.    (Table 1). No significant differences in tobacco and alcohol consumption, andrology history, and pre-cancer paternity were observed between the categories (Table 1). Twenty-one percent of the patients had at least one child at the time of the diagnosis, however, the information was missing for one-third of the patients (121 patients).

| Sperm parameters
Sperm concentration was significantly lower in patients with testicular cancer compared to the other cancer groups (hematologic, prostate, and colorectal neoplasia). No statistical differences were observed between the studied groups for the volume of the ejaculate, the sperm progressive motility, and the number of frozen straws per sample. Regression analysis also confirmed a lower semen concentration in the testicular cancer group compared to the hematologic malignancies group (Table 2).  and 39 were frozen ET. The overall fertilization rate (FR) and implantation rate (IR) reached 60.5% and 29.6%, respectively.

| Fertility outcomes
The characteristics of the cohort including maternal age, sperm parameters, indications, and fertility outcomes are provided in Table 3 and Supporting Information. No correlation was observed between sperm concentration and pregnancy success. No significant differences in the sperm parameters were observed between the sperm of patients who achieved pregnancy and those who failed.

| DISCUSSION
Testicular cancer and hematologic (leukemia and lymphoma) malignancies are the main indications of sperm freezing in our population, which is in line with the literature. 10,15,18 Overall, more than 30% of patients were oligozoospermic at the time of diagnosis. Almost 20% of them had severe oligozoospermia according to WHO 2010 semen analysis criteria (<5 million/ml), half of whom being testicular cancers. 19 We confirmed that sperm concentration was significantly lower among testicular cancer patients compared to other cancer types (hematologic including both leukemia and lymphoma, prostate, neurological and colorectal cancers). A hypothesis being the direct cancer effect on spermatogenesis impairment and the indirect effect related to endocrine and systemic disturbances. 20 It is worth noting that the decline in sperm quality among testicular cancer patients is often associated with local inflammation, a history of cryptorchidism, and/or hypospadias referred as "testicular dysgenesis syndrome." 21 T A B L E 1 Characteristics of the population according to the type of neoplasia: H, T, P, GI, N, and O  26,27 Nevertheless, these parameters should be taken into account in an andrology assessment as they induce oxidative stress and DNA damage. [28][29][30] Age was also considered as an important parameter as a metaanalysis showed a trend of a lower sperm concentration with increasing paternal age, due to endocrine disruptors and accumulated oxidative stresses. 31  cryopreservation before any potential gonadotoxic treatment irrespective of their previous fertility history. [8][9][10]17 In our cohort, only 28 patients (9.33%) returned to attempt conception using assisted reproduction technology ART (38 IUI cycles, 1 IVF, and 46 ICSI cycles) after a median time of 4.25 years.
This is in line with the literature, with the usage rate varying from 7.5% to 10.3%. 7,24,33 Among the 38 IUI cycles with frozen-thawed sperm, five patients achieved a pregnancy, and four healthy babies were born. After IUI failure, seven patients went for an ICSI procedure which succeeded in pregnancy and delivery for five of them. With regards to age among cancer survivors who returned for ART, we found a statistically significant difference between the F I G U R E 2 Distribution of concentration in millions per ml (A), volume in ml (B), and progressive motility (C) of the studied population and six cancer groups sperm analysis, according to the WHO 2010 reference values. groups for male age, the testicular cancer group being the youngest compared to the other group (p = 0.004).
A total of 91 embryos were transferred: 52 were fresh ET and 39 were frozen ET, overall FR was 60.5% and IR was 29.6%. We obtained comparable IR of 36.2% and 20% for testicular cancer and hematologic group respectively as found in the literature. 15 Another study on the clinical outcomes of ART included 34 ICSI and 11 frozen ET reported IR of 22% and 25% for day 3 and day 5 ET. 17 It should be noted that among the patients who failed to conceive, two patients were still under ART treatment, two couples had separated during the ART procedure, one patient refused IVF, one patient changed to another hospital, and one patient had cancer recurrence before being able to have a child.
Finally, a 2021 study compared thawed sperm versus fresh sperm used for IVF/ICSI in cancer patients. The pregnancy rates and live birth rates were similar in the two groups. 16 In our study, we did not observe any correlation between the frozen sperm concentration and fertility outcomes. These results are important to promote sperm cryopreservation before oncological treatment and should be discussed during fertility preservation counselling.
Our limitations are related to the retrospective design of the study, that some data were missing, and for 19 cancer patients their sperm sample did not enable a freezing procedure (extremely poor sperm sample without enough motile sperm for freezing, and/or azoospermia) but the azoospermic rate was not evaluated in the present study as they were not always identifiable in the patient's selection.

| CONCLUSION
Sperm quality at cancer diagnosis is often compromised by the disease and any given gonadotoxic treatment will further diminish fertility. We analyzed sperm quality in a large cancer patients' cohort and included their fertility outcomes. The main findings were the significant reduction in sperm quality in testicular cancer patients, with a significant correlation found between sperm concentration and cancer type as well as patients' age. However, we showed no correlation between sperm concentration and fertility outcomes. Our results further confirm the negative impact of cancer on sperm quality without affecting ART success rate, which is utterly important as a male reproductive health perspective for cancer survivors. All cancer patients should be counselled and offered fertility preservation options as a gold standard.

DATA AVAILABILITY STATEMENT
The data are available on request from the corresponding author.

TRANSPARENCY STATEMENT
David Pening affirms that this manuscript is an honest, accurate, and transparent account of the study being reported; that no important aspects of the study have been omitted; and that any discrepancies from the study as planned (and, if relevant, registered) have been explained.

ETHICS STATEMENT
The study was approved by the Erasme Ethical Committee (P2019/397).